Stainless Steel S40975-ANN (Annealed)
Heat-treated state · default condition
UNS S40975
Standard stocked condition for converter shells, exhaust tubing and stampings — maximum formability and weldability.
Values for the ANN condition
Other S40975 tempers and conditions
S40975 is listed in 2 conditions; see the grade overview at S40975.
- ANN
- TR
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefaultThis page Annealed | Standard stocked condition for converter shells, exhaust tubing and stampings — maximum formability and weldability. | 250 | 440 | 30 | 145 HB | — |
Temper Rolled | Slight cold work for improved flatness, stiffness and stretcher-strain suppression in roll-formed shells. | 350 | 490 | 22 | 178 HB | 2.9 % IACS |
What is S40975-ANN?
S40975-ANN is S40975 heat treated to ANN — standard stocked condition for converter shells, exhaust tubing and stampings — maximum formability and weldability. S40975-ANN has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 91% of stainless steel grades. Elongation at break is 30% and the elastic modulus is 200 GPa (29 Msi). S40975-ANN has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,450°C (2,642 °F).
Advantages
- Easy to machine — 55/100, better than 94% of stainless steel grades
- Forms and bends easily — 80/100, better than 93% of stainless steel grades
- Low embodied carbon — 3.4 kg CO₂/kg, better than 91% of stainless steel grades
- Conducts heat well — 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 87% of stainless steel grades
- High electrical conductivity — 2.9 % IACS, better than 87% of stainless steel grades
Limitations
- Low strength — 250 MPa (36.3 ksi), worse than 91% of stainless steel grades
- Needs corrosion protection — 42/100, worse than 90% of stainless steel grades
- Hard to polish — 55/100, worse than 89% of stainless steel grades
S40975-ANN properties
Typical room-temperature values for S40975-ANN; 10 are specific to this condition. Other listed values are S40975 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
S40975-ANN has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,450°C (2,642 °F).
Mechanical15
S40975-ANN has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 91% of stainless steel grades. Elongation at break is 30% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
S40975-ANN is rated for continuous service to 675°C (1,247 °F). It conducts heat at 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 87% of stainless steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
S40975-ANN conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (42/100), worse than 90% of stainless steel grades.
Sustainability4
Producing a kilogram of S40975-ANN takes about 42 MJ of energy and emits 3.4 kg of CO₂ — less than 95% of stainless steel grades. Typical recycled content is 70%.
Manufacturability6
S40975-ANN's machinability is good (55/100, better than 94% of stainless steel grades); weldability very good (78/100); formability very good (80/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S40975-ANN
Is S40975 easy to machine?
Machines like a soft low-alloy steel but is somewhat gummy — use sharp, positive-rake carbide, rigid setups, 0.1–0.3 mm/rev feeds and flood coolant to avoid built-up edge.
Can S40975 be welded?
Readily GTAW/GMAW/resistance/laser welded without post-weld anneal thanks to Ti stabilization; keep heat input low to limit HAZ grain growth, use 409Cb/430Ti or 308L/309L filler, and back-purge to avoid oxidation.
Can S40975 be formed, bent or molded?
Excellent roll-forming, deep-drawing and tube-bending behaviour with r-value typical of stabilized ferritics; watch springback and roping/ridging on heavily drawn panels.
What surface finishes work on S40975?
Normally used as-pickled or aluminized/painted; can be bead-blasted or brushed, but it stains in salt exposure — passivation or coating is recommended for cosmetic outer parts.
S40975 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Clow-carbon stabilized ferritic | ≤ 0.03 | 0.02 |
| Mn | ≤ 1 | 0.4 |
| Siaids high-temperature oxidation resistance | ≤ 1 | 0.5 |
| P | ≤ 0.04 | 0.03 |
| S | ≤ 0.02 | 0 |
| Cr | 10.5 – 11.75 | 11.2 |
| Nideliberate Ni addition for toughness / HAZ ductility (distinguishes S40975 from S40910/S40920) | 0.5 – 1 | 0.75 |
| TiTi ≥ 6×(C+N) for stabilization | 0.1 – 1 | 0.25 |
| N | ≤ 0.03 | 0.02 |
| Fe | balance | — |
S40975-ANN — frequently asked
What is S40975-ANN used for?
S40975-ANN is typically used for catalytic converter shells, exhaust heat shields, welded exhaust tube and pipe, muffler shells, exhaust flanges and brackets and deep-drawn exhaust end caps. In short: most formable 409 variant; converter-shell workhorse; good weldability, no PWHT.
What is the yield strength of S40975-ANN?
S40975-ANN has a typical yield strength of 250 MPa (36.3 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 91% of stainless steel grades. Strength varies by condition: see the 2 listed tempers.
Is S40975-ANN easy to machine?
Reasonably — machinability is rated good (55/100, better than 94% of stainless steel grades). Machines like a soft low-alloy steel but is somewhat gummy — use sharp, positive-rake carbide, rigid setups, 0.1–0.3 mm/rev feeds and flood coolant to avoid built-up edge.
Can S40975-ANN be welded?
Yes — weldability is rated very good (78/100). Readily GTAW/GMAW/resistance/laser welded without post-weld anneal thanks to Ti stabilization; keep heat input low to limit HAZ grain growth, use 409Cb/430Ti or 308L/309L filler, and back-purge to avoid oxidation.
What surface finishes work on S40975-ANN?
Normally used as-pickled or aluminized/painted; can be bead-blasted or brushed, but it stains in salt exposure — passivation or coating is recommended for cosmetic outer parts.
Can S40975-ANN be formed, bent or molded?
Excellent roll-forming, deep-drawing and tube-bending behaviour with r-value typical of stabilized ferritics; watch springback and roping/ridging on heavily drawn panels.
What is the maximum service temperature of S40975-ANN?
S40975-ANN is rated for continuous use to about 675°C (1,247 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between S40975-ANN and S40975-TR?
ANN is the default condition — standard stocked condition for converter shells, exhaust tubing and stampings — maximum formability and weldability. TR: slight cold work for improved flatness, stiffness and stretcher-strain suppression in roll-formed shells. Yield strength is 250 MPa in ANN versus 350 MPa in TR.
Sources
- ASTM A240/A240M — Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip — ASTM International (2023)
- ASTM A268/A268M — Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing — ASTM International (2022)
- ASTM A1010 / SAE J405 UNS designations for stainless steels — ASTM / SAE (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Type 409 / 409 Ni ferritic stainless steel product data — AK Steel / Cleveland-Cliffs (2020)
- Stainless steel grade datasheets (ferritic 4xx series) — Outokumpu / worldstainless (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.